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(No Model.)

2 Sheets-Sheet 1.

C. SCHAEPBR. STEAM BoILBR. No. 437.384.

Patented Sept. 30, 1890.

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(No Model.) 2 sheets-snee@ 2. C. SCHAEFER. STEAM BOILBR. No. 437,384. Patented Sept. 30. 1890.

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lil l l I l l i l l l l UNITED STATES PATENT l OFFICE.

CARL soHAEEER, or oRERHAUsEN, GERMANY.

STEAM- BOILER.

SPECIFICATION forming part of Letters Patent No. 437,384, dated September 30, 1890.

Application filed April 26, 1889.

To all whom, it may concern.-

Be it known that I, CARL SCHAEEER, a sub-l ject of the Emperor of Germany, residing at Oberhausen, in the country of the Rhine, in the Kingdom of Prussia, in the Empire of Germany, have invented a certain new and useful Improvement in the Construction of Steam-Boilers, of which the following is a full and exact description.

This invention relates to an improvement in boilers, and is based upon the following motives-that is to say, it is a fact well known that the ever-increasing tension of steam required for steam-boilers, and more particularly for marine boilers, necessitates the employment of sheet-iron of such a thickness as will render it impossible, or nearly impossible, to Work the said sheet-iron into boilers by means of the usual appliances as now commonly in use in even the larger boiler-factories. Moreover, it is known that in bending into the shape of boilers sheet metal ot' great or uncommon thickness the material of said metal is apt to become distorted and strained by reason of the exterior fibers more distant from the neutral layer being stretched too much, while the layer of iibers on the interior surface are jolted in too high a degree, so that the resistability of the sheet metal, after bending the latter intoform, is materially diminished and impaired. Finally, it is to be remarked that the cost of sheet metal increases in an undue measure or proportion with the higher weight due to the increasing thickness.

N ow, in order to obviate the above difficul-v ties, it is proposed in accordance with the present invention to employ for the casings of boilers or other vessels intended for high pressure, in lieuof one plate of sheet metal having the required final thickness of the boiler two or more superposed sheet-metal plates of reduced thickness, so that the several combined thicknesses of the said several plates will equal the thickness which the one sheet-metal plate would have to have if such single plate had been used for the con` struction of the boiler. If, for instance, a boiler-casing were to have a thickness of two thickness two sheets .of one inch each, or three sheets of two-thirds inch each, or four sheets of one-halt' inch each, would have to be taken and connected togetherin a suitable manner. Connecting said sheet-metal plates is preferably effected so Athat the one plate will cover up the joint between two other plates, and that the said joint is at the same time connected by means of a rivetedshplate. Moreover, it is deemed advisable to provide with suitable fish-plates all the circumferential circular and longitudinal joints on the outside and the longitudinal joints on the inside of the boiler, the circular joints on the interior requiring to be coveredA up by a fish-plate only in case of extremely high pressure being employed. l

Figure l is a longitudinal section of my improved boiler. Fig. 2 is across-section through Fig. 1. Fig. 3 is a longitudinal4 section of a modified form thereof.A Fig. 4t is a cross-section through Fig. 3.

Referring first to the steam-boiler indicated in Figs. l and 2, it will'be noticed that the said boiler is provided with a easing formed v by two superposed sheet-metal plates aand b. c c designate interior, and cl d exterior, fishplatesrfor the circular joints, while e e are interior, and ff exterior, fish-plates for the longitudinal joints.

Referring next to Figs.` 3 and 4, the boiler therein illustrated is composed of a casing consisting of three superposed sheet-metal plates h, t', and k, and fish-plates Z, m, n, and o, for the interior, intermediate, and exterior circular and longitudinal joints.

It will be readily seen that the boilers constructed as herein described consist of acasing having, as it were, no joint at all, there being, in fact, no joint entering the said casing further than to one-half or to one-third, &c., of the thickness of the metal. Moreover, it is evident that considering the fact accordingl to Which the entire length and Width of each metal plate is always covering up the joint of the adjacent plates, a more reliable connection of the several plates, as well as a more perfect closing up of the joints, is insured by reason of the broader cover surinches, then, according to the present invention, instead of one metal plate having said rounding the said joints.`

By means of the above arrangements I am ICO enabled to increase to any desired thickness the casings of steam-boilers Without at the same time resorting to the use of sheet-metal plates of proportionately-increasing thickness, and thus to produce from relatively thin plates boilers having large diameters and apt to sustain the highest possible pressure, it being noticed that the manufacture of such boilers and the Working of the thin plates and boiler-casings by means of the plant and appliances as heretofore and now in use in the boiler-Workshops cannot meet Withany difficulties. l

Having thus described my invention, what Iclaim as new, and desire toV secure by Letters Patent, is-

Riveted boilers, and the like, the casings of which are composed of two or more superposed separate sheet-metal plates, arranged so that the joint between two such plates is covered by one or more of the adjacent plates of the casing, the said latter plates doing at the same time the office of ish-plates, in coinbination with additional narrow lish-plates CARL SUHAEFER.

TWitnesses# HERMANN KUHFUs, EDUARD WEINREICH. 

